Nonlinear Finite Elements

MotionSolve 14.0 introduces the “NLFE Body” which allows you to model non-linearly flexible components in your multi-body system. This is an experimental feature in the current version. The NLFE Body is based on the Absolute Nodal Coordinate Formulation (ANCF). Nonlinearity can occur for two main reasons: (A) Geometric nonlinearity and (B) Material non-linearity. The NLFE body supports both.

MotionView has new capabilities for modeling NLFE systems. A generic NLFE Body can be created using either the CABLE or BEAM element.

The CABLE element does not resist shear or torsion forces. This implies that the cross section of this element does not change as the entity deforms.

This element can be used to model cables, wires, ropes, etc. Only the Linear Elastic material model is supported.

The BEAM element resists all forms of deformation, which implies that the cross section can also deform with load. This can be visualized in HyperView while using this element.

Multiple cross sections are supported for the BEAM element:

•	Circular (solid and hollow)

•	Rectangular or Box (solid and hollow)

•

Channel

•

Cross

•

Hat

•	H, I, L, T and Z sections

This element can be used to model beams, springs, belts, rubber components etc. You may choose from either a Linear-Elastic or a Hyper-Elastic material.

Three Hyper Elastic materials are supported – Neo-Hookean Compressible, Mooney-Rivlin and Yeoh models. MotionView provides a set of recommended values for the model parameters. You may however, create new materials and enter your own parameters.

MotionView provides 3D visualization of the NLFE body based on the profile and cross section properties.

An NLFE body can now have a pre-loaded position in addition to the model position. The user can import these in a CSV format. Upon import, the model position will be shown in wireframe mode and the loaded position in solid.

With a combination Save command in MotionSolve and a Python script, it is now possible to save the configuration of the NLFE at the end of simulation into a CSV file. This csv file can be read into MV as preloaded configuration. An option is also available to visualize the unloaded and pre-loaded profile together.

In addition to the generic Cable and Beam modeling elements, MotionView also supports a small set of NLFE subsystems that are specific to the Auto industry. These subsystems may be accessed from the vertical toolbar to the left of the graphics window. The following subsystems are supported.

Stabilizer bar

mbs_14_11

Coil spring

mbs_14_12

Refer to NLFE Subsystems to learn more about using these subsystems in your model.

MotionSolve supports a much larger set of NLFE modeling elements. You can use these in a MotionView model by using a Templex template. Native MotionView support is not available at this time.